Common law marriage—also known as marriage without formalities or informal marriage—is marriage without a wedding or marriage ceremony and without a marriage license. Some states recognize common law marriage under certain circumstances—such as when the parties agree to be married, live together (cohabit) after agreeing to be married, and represent to others that they are married (holding themselves out as a married couple).

Other states previously recognized common law marriages, but no longer recognize such marriages after a certain date on which the law was changed—usually by statute. In other states, common law marriage has not been recognized by the legislature in a statute, but the courts have recognized common law marriage in court opinions or case law.

Delaware does not recognize common law marriages created within the state. This means that couples cannot become legally married in Delaware without obtaining a marriage license and having a formal ceremony. However, Delaware does recognize common law marriages that were established in other states where such marriages are legally recognized, provided that they meet the requirements set forth by those states. This recognition is based on the principle of comity, which allows for respect of the laws and judicial decisions of other states. Therefore, if a couple has a valid common law marriage from another state, Delaware would consider them married for legal purposes. It is important for individuals in such relationships to understand that without a recognized common law marriage or a formal marriage, they may not have the same legal rights and obligations as a married couple under Delaware law.